Water is the inheritable solvent for a wide variety of dissolved salts, simple and complex. Saline waters such as sea water, brine water, oil-field brine water, formation water, brackish water, ground water, salt lake water, make-up saline solution, and the like are usually high in some of the following species: (1) Salts: chloride salts, sulfate salts, carbonate salts; (2) Scale Salts: barium, calcium, and strontium in the form of sulfates, carbonate and silicates; and (3) Naturally Occurring Radioactive Materials (NORM) contaminant salts, or the decay chain of uranium (.sup.238 U, .sup.234 Th, .sup.234 U, .sup.230 Th, .sup.226 Ra, .sup.222 Rn, .sup.218 Po, .sup.214 Pb, .sup.214 Bi, .sup.214 Po, .sup.210 Pb, .sup.210 Bi, .sup.210 Po, and .sup.206 Pb). Such species are rendering saline waters either unusable (e.g., high total dissolved solids) or posing serious disposal problems (e.g., disposing brine stream from membrane processes and NORM contaminant salts), industrial problems (e.g., scale formation), and health and environmental concerns.
The scarcity of natural resources of usable water in arid and semi-arid areas has a significant impact on the economic development. Conventional desalination and membrane separation technologies present relatively expensive technologies to separate salts form saline waters, which are applicable primarily on a regional basis. Further, the relatively high cost of water redistribution appears to preclude the economical transportation of water over long distances. Consequently, the agricultural growth in arid areas for instance, is restricted because of a limited usable water supply.
The concentrations of salts and scale salts in saline water are quite high, and thus the permeate (product) stream is limited to about 70% of the overall feed stream in conventional desalination processes such as membrane processes. The disposal of the remaining 30%, which is the brine stream, is a challenging engineering task. Such a task would include economic considerations, technical difficulties, and environmental regulations. Therefore, a need exists for a process, to service as an integral part of hybrid system in conjunction with membrane or other saline water conversion processes, to concentrate and reduce further the brine stream. Such a process could significantly mitigate and reduce the disposal problem.
A large volume of saline water is produced and associated with the exploration and production of petroleum, gas, coal, and fossil fuel. Several problems are associated with the produced saline water. First, scale salts and formation have a substantial impact on facilities of petroleum, gas, coal, fossil fuel and other industries since it: (1) restricts production flow; (2) causes equipment inefficiencies; (3) impedes heat transfer; and (4) damages equipment and increases shutdown time. Further, the ubiquity of uranium and thorium in the crust of the earth suggests that NORM contaminant salts will be common wherever produced saline water is salty, hot and depleted in sulfate. The uranium daughters including .sup.238 U, .sup.234 Th, .sup.234 U, .sup.230 Th, and .sup.226 Ra are chemically active and attached themselves to nearby solid materials. As such, scale salts can become radioactive due to attachments of NORM contaminant salts. Second, the produced saline water can adversely contaminate and affect soil and vegetation. Third, serious health and environmental problems are associated with produced saline water.
Currently, there is no satisfactory method or process to separate and concentrate scale salts and NORM contaminant salts from saline waters or contaminated soils. Downhole disposal is the available option for the disposal of such species. However, economic, technical, and logistic considerations are associated with such an option. Further, downhole is inappropriate for high volume salt streams such as contaminated soils. As such, a process for the separation and concentration of scale salts and NORM contaminant salts from saline waters and contaminated soils is urgently needed. Such a process could concentrate and reduce the scale salts and NORM contaminant salts, and thus could make the downhole disposal a more feasible option.
The above situations have led me to invent the process that is described in this invention to alleviate the problems associated with the use and production of saline waters and contaminated soils.